Tag: Melanesia

How many immigrants does it take to make a migration?

When presented with a sample comprising only 3+1 skulls, both scientific caution and parsimony suggest you should assume that colonists coming ashore back at the beginning of human history in Vanuatu and Tonga were probably more diverse, biologically speaking, than is witnessed by these four—at least until there is further evidence showing they did indeed come not just from a genetically homogeneous place of origin, but also a place where the inhabitants were as sui generis as they appear to be vis-à-vis others on earth (Skoglund et al. 2016: fig. 1b).

Logic such as this is well worth attending to. But in this instance, there is an equally logical way to get around the usual working assumption that people are likely to be more diverse than first appearances may suggest. Given how poorly specified are the two hypotheses under scrutiny here, it is anyone’s guess how big we are supposed to think the boats must have been that brought early colonists to Vanuatu and Tonga around three thousand years ago. Even granting they may have arrived in more than one canoe, it would be reasonable to assume those arriving were fairly few in numbers. If so, then there is no need to assume blindly that those who came ashore in Vanuatu or Tonga constituted a representative (random) sample of the real human genetic diversity among those back home in the places where they came from, wherever on earth that was (Terrell 1986).

Furthermore, this is not all that might be reasonably assumed when trying to pin down the who, what, where, why, and when behind these four skulls. The number of pioneering colonists arriving in canoes from elsewhere with them or before them may not only have been relatively few. They may also have been kin, i.e., biologically related to one another. If so, then possibly what makes these crania look sui generis in comparison with other people on earth, living and dead, may just be that we are seeing a “family resemblance” in these human remains (Terrell 1986; Walker and Hill 2014).

Homeward bound

For journalists and others, the real mystery of these remains, of course, is where these pioneers or their immediate forebears sailed from when they launched their boats to start a new life elsewhere. What is now known or can be reasonably assumed, therefore, about places to the west where they may have sailed from?

Until the Holocene stabilization of sea levels in the southwestern Pacific around 8,000–6,000 years ago, it is likely that much of the northern coastline of New Guinea was steep and uninviting of human settlement (as much of it still is today) except perhaps where favorable local circumstances may have at least temporarily trapped sediment in sandbars, coastal lagoons, and small river deltas. Little is currently known archaeologically about this coastline, which runs east-west for roughly 1,500 miles (2,400 km), and which would logically have been the most likely route between Asia and the farther reaches of the Pacific (Golitko et al. 2016). The best guess at the moment is that few people lived along this coast for the first 35,000–45,000 years of human history in the Pacific (Terrell 2006). In effect, earth and sea conspired to isolate New Guinea, like a sleeping giant, from frequent contact with islanders elsewhere both to the east in what is now popularly called Melanesia, and to the west in Island Southeast Asia (for biological support for this inference, see: Matisoo-Smith 2016: 391).

Following the Holocene stabilization of sea levels, however, coastal areas in Southeast Asia and the Pacific began to develop into rich floodplains, river deltas, and lagoons. By the mid Holocene, it is probable that people in the island realms to the east and west of New Guinea began to deal with one another back-and-forth more often as coastal people began to travel with greater reach along this immense island’s lengthy northern coastline (Torrence and Swadling 2008).

West meets East

Contrary to the notion that there are only two hypotheses about the prehistoric human settlement of the more remote islands in the Pacific east of New Guinea, there are numerous variants not only of those two old ideas but of others, too (for a recent review, see: Matisoo‐Smith 2016). Here we will introduce only one plausible reconstruction (Terrell, in press).

Initial baseline assumptions

Archaeologists now think people have been living in Southeast Asia for 50,000 years or so, and perhaps for not quite so long in the islands just east of New Guinea as far as Bougainville in the Northern Solomons.

The gradual flooding of the Sunda paleocontinent in what is now Southeast Asia since the Last Glacial Maximum ~21,000 years ago created extensive coastal environments that were ecologically rich and productive (Sathiamurthy and Voris 2006; Hanebuth et al. 2011: fig. 2). Similar extensive flooding did not occur in the area east of New Guinea labeled as Parkinson’s Islands (after the early ethnologist Richard Parkinson) on the map above (Lavery et al. 2016).

Due to this environmental advantage, it is probable that there were far more people living in Southeast Asia 6,000 years ago than there were in Parkinson’s Islands.

By the mid Holocene—contrary to the prevailing assumption in historical linguistics that doesn’t take this ecological advantage into consideration—it is probable that languages classifiable as Austronesian were widely spoken throughout Wallacea and elsewhere in Southeast Asia even as far north as Taiwan. But not yet in Parkinson’s Islands which had been isolated from Asia by the island of New Guinea.

Throughout the Late Pleistocene and early Holocene, Wallacea and Parkinson’s Islands were both areas of the Pacific where the advantages of travel by sea rather than by land nurtured the use of canoes and the development of local navigational methods and skills.

Canoes equipped with outriggers and sails were invented in Southeast Asia at some point in the Late Pleistocene or early Holocene. Simple dugout canoes remained the predominant boat type used for travel among coastal communities in Parkinson’s Islands.

Modeling the relocation of immigrants from Wallacea

A small Austronesian-speaking hamlet or village community left home for some particular local reason or reasons from somewhere in Wallacea—or possibly on the north coast of New Guinea—and made landfall in the Bismarck Archipelago.

It is possible that wherever it was they came ashore, they arrived not as strangers but rather as old friends of some of the local people there in the Bismarcks (Terrell 2015).

Among these immigrants were individuals skilled at pottery-making, and also skilled in the arts and rituals of building and sailing outrigger canoes with sails. Both of these technologies were new to the Bismarcks region. Moreover, such skills may not have arrived at the same time if travel back-and-forth between communities in Wallacea, northern New Guinea, and the Bismarcks became routine at least for awhile.

The local people not only welcomed them, but often also acquired new ways of doing things—such as the art of pottery-making—from their immigrant neighbors, in some instances even their foreign language skills. The reverse may have also been true.

Time passed, generations came and went. For now unknown reasons, it eventually became fashionable, prestigious, or perhaps even necessary for some people in the Bismarcks to set sail for islands yet farther to the south and east in the Pacific, although how many people in how many communities were involved, how often they sailed away, and for how many years this voyaging away from home in the Bismarcks went on are now all unknown and perhaps unknowable.

Even so, considering the passage of the time between (a) the first arrival of immigrants from the west and (b) the departure of some people generations later to settle down in other (more remote) places to the southeast, there is no reason to insist that these two separate episodes of human resettlement were similarly inspired or motivated (Walker and Hill 2014).

Furthermore, given that both the voyaging technology and navigational skills required to colonize the more remote islands of the Pacific may have been available then only in some communities in the Bismarcks, it is not surprising that early settlers in Vanuatu, Tonga, and elsewhere had similar material culture traits (i.e., the so-called “Lapita cultural complex”).

Conclusions

Because the first immigrants who reached Vanuatu and Tonga were entering a vast and uninhabited part of the Pacific, it is probably not surprising that many nowadays have been seduced by the modern global distribution of Austronesian languages—from Madagascar to Rapa Nui (Easter Island) and from New Zealand to Taiwan—into thinking that such a vast geographic compass could only be the historical product of some kind of massive human migration that was singularly intentional and singularly premeditated from the very moment the first Austronesian-speaking immigrant stepped into the first canoe to sail from somewhere in island Southeast Asia or on the north coast of New Guinea to the Bismarcks 3,000 and more years ago. It is wise to remember, therefore, that appearances can be deceiving.

Furthermore, today we know nothing about marriage (or sexual) practices in the Pacific in the prehistoric past. Although it is stating the case too simply, we do know that the basic building block of human genetic relatedness is the gene. Anyone who knows about the birds and the bees knows that genes can travel far and wide through sexual intercourse even if the people carrying them may only get as far away from home during their time on earth as the next village or two down the road. Consequently, there is no a priori reason to assume that race = language = culture. Or that genes necessarily traveled the Pacific millennia ago as the exclusive and enduring “property” of a massive and self-contained ethnic or ethnolinguistic migration that was able to keep its collective act together over thousands of miles and for hundreds, even thousands, of years. As some anthropologists like to say it, we need models of Pacific prehistory to work with that are “on the ground,” not “pie in the sky.”

Although we have been talking here almost exclusively about the Pacific Islands, the issue at stake is a global one. It is not just worrisome to find that even scientists may sometimes be unaware of the intellectual racism hidden in the conviction that the story of our species is a tale about ancestry, ancient migrations, and admixture. Commonsense ideas like these can be more than misleading. They can lend credence to other notions and old prejudices that can be harmful and sometimes deadly.

Acknowledgments

We thank Ethan Cochrane, Mark Golitko, Tyrone Lavery, Lisa Matisoo-Smith, and Robin Torrence for assistance in the preparation of this 3-part commentary.

References

Bellwood, Peter. 2011. Holocene population history in the Pacific region as a model for worldwide food producer dispersals. Current Anthropology 52: S363–S378.

Matisoo-Smith, Elizabeth A. 2016. Human biology and population histories in the Pacific–Is there such thing as a Lapita people?. In: The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands, edited by M. Oxenham and H. Buckley, pp. 389–408. Routledge, London.

Terrell, John Edward. 2015. A Talent for Friendship. Oxford University Press.

Terrell, John Edward. In press. Understanding Lapita as history. In Oxford Handbook of Prehistoric Oceania, edited by Ethan Cochrane and Terry Hunt. Oxford University Press.

Terrell, John Edward, John Edward, Terry L. Hunt, and Chris Gosden. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 38: 155–195.

Necessary, plausible, and sufficient

Nobody, as far as we know, has come up with a universally accepted checklist of what makes a scientific hypothesis about anything something worth paying attention to. There are three criteria, however, that strike us as items that ought to be on such a checklist. Here is how we see these three applying to the conclusions now being made about the biological origins of the Polynesians.

Visualization by David Eccles of the two popularly assumed racial migrations from Asia out into the Pacific. Source: https://commons.wikimedia.org/wiki/File:Polynesian_Migration.svg

Necessity: What needs to be explained? Both of the hypotheses weighed by the 31 contributors to the paper in Nature (Skoglund et al. 2016) under discussion here are alternative ways of trying to understand certain widely accepted observations about islanders in the Pacific: (a) people in Polynesia speak languages assigned by linguists to the Austronesian (Malayo-Polynesian) family, as do many people in Melanesia and Island Southeast Asia; (b) archaeologists now generally agree that what they have labeled the “Lapita cultural complex”* dating to ca 3300–2800 cal BP (Specht et al. 2016) exhibits a mix of cultural traits, some local to Melanesia and others apparently having roots to the west in Island Southeast Asia (Specht et al. 2014); and (c) the Lapita skulls found in Vanuatu and Tonga are morphologically and genetically sui generis (as the authors of this paper note, in some respects these four individuals are unique unto themselves).

Plausibility: The two hypotheses considered by this consortium of scholars differ in their plausibility. (a)The idea that people traveled directly from Taiwan to Vanuatu and Tonga is basically impossible to assess given that nothing is said about how they might have done so—a striking omission considering the major dimensions of space and time involved. (b)The second hypothesis put on the table is similarly deficient, but it at least acknowledges that the set of material culture traits associated with the four Lapita skeletons in Vanuatu and Tonga wasn’t imported in toto direct from Taiwan.

Sufficiency: As Richard Levins observed years ago, truth is the intersection of independent lies. (a)Not only are the two hypotheses considered by this consortium of authors basically left unspecified, but (b) no reason is given for limiting the field of possible hypotheses solely to the two considered by these contributors.

The problem of equifinality

In light of #2 and #3 just noted, consider the old cliché “there is more than one way to skin a cat.” If you are a feline lover, there is even another way of saying more or less the same thing. As the biologist Ludwig von Bertalanffy made famous in the last century, you can call it equifinality. However phrased, it is wise to remember there is usually more than one way to get from A to Z, or even just A to B. The corollary relevant to the present discussion is that one cannot just assert that B came from A without offering a sufficient explanation for how that would have been possible. And more to the point, granting for the sake of discussion that B did somehow come from A, the scientific way of doing the job that needs to be done entails offering more than just 1–2 inadequately specified hypotheses.

The absence of evidence is not evidence of absence

According to these 31 authors: “our modelling indicates that Philippine populations (Kankanaey) are the closest outgroup to the First Remote Oceanians [i.e., these 4 skulls], indigenous Taiwanese (Atayal) second closest, and mainland southeast Asians such as the Dai most remote, consistent with models of population movement along a route from Taiwan to the Philippines to Near Oceania to Remote Oceania.” Maybe yes, maybe no.

Recall that only 14 of the 83 places in their modern comparative genetics sample are located in Island Southeast Asia, and none of the other 69 localities included in their analysis is in the region between the Philippines and northern New Guinea except for a single sample of 10 individuals from Sulawesi.Now look at a map of the region in question (see below).

Note two things, in particular. First, if it is true, as the song goes, that it’s a long, long way to Tipperary, then it is an even longer way from (A)Taiwan to (B) Tonga—more than 5,300 miles (8,500 km) in a straight line if a bee could fly that way that far. Second, notice the total lack of genetics samples from the big gap between the Philippines and the Bismarck Archipelago east of New Guinea (the few samples from New Guinea don’t count for reasons we will not go into here).

You don’t have to be a grumpy skeptic, therefore, to ask: if the four Lapita skulls from Vanuatu and Tonga look genetically most like people today in the Philippines, what about folks today, say, in the Moluccas and Halmahera off the Bird’s Head region of western New Guinea? And possibly also people living along the north coast of New Guinea itself? Must we assume these four individuals from Vanuatu and Tonga somehow came all the way from Taiwan or the Philippines to come ashore there?[*]

*The three skulls from Vanuatu were not found with the rest of their skeletons (Skoglund et al. 2016: supplementary notes). How they had been buried as well as their condition as skulls prior to burial suggest they had been cared for as portable heirlooms for an unknown period of time after death: “Ancient DNA was successfully obtained from three skulls from striking mortuary contexts: a jar burial containing a single skull (B17), an alignment of three skulls lying on the chest of a skeleton without a skull (B10B)”. There is a possibility that these individuals might have been long dead before their skulls arrived in Vanuatu. In contrast, with regard to the single individual from Tonga: “Ancient DNA was successfully obtained from the right petrous bone of burial SK10, a single primary interment of an adult female . . .”.

References

Bellwood, Peter. 2011. Holocene population history in the Pacific region as a model for worldwide food producer dispersals. Current Anthropology 52: S363–S378.

Matisoo-Smith, Elizabeth A. 2016. Human biology and population histories in the Pacific–Is there such thing as a Lapita people?. In: The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands, edited by M. Oxenham and H. Buckley, pp. 389–408. Routledge, London.

Terrell, John Edward. 2015. A Talent for Friendship. Oxford University Press.

Terrell, John Edward. In press. Understanding Lapita as history. In Oxford Handbook of Prehistoric Oceania, edited by Ethan Cochrane and Terry Hunt. Oxford University Press.

Terrell, John Edward, John Edward, Terry L. Hunt, and Chris Gosden. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 38: 155–195.

Here’s a hint about why scholars can be so captivated by what is basically an old-fashioned racial migration argument. They are apparently forgetting what they have been taught about the difference between a rhetorical argument and a scientific one.

The is part 1 of a 3 part commentary

THE IDEA THAT ONCE UPON A TIME the many islands of the South Pacific were colonized by different racial migrations out of Asia or the Americas (the latter a minority view) is as old as the hills. Or at any rate, at least as old as the earliest known encounters after 1492 between Europeans and the people living there.

1852 Bocage Map of Australia and Polynesia. The colored boundary lines show how this part of the world has long been subdivided into four cartographic regions labeled here as Malaisie (Malaysia), Micronesie (Micronesia), Polynesie (Polynesia), and Melanesie (Melanesia). Source: https://upload.wikimedia.org/wikipedia/commons/a/a2/1852_Bocage_Map_of_Australia_and_Polynesia_-_Geographicus_-_Oceanie-bocage-1852.jpg

The apparent remoteness and isolation of these islands and their inhabitants have long fueled the notion that here, if not necessarily elsewhere on earth, “race, language, and culture” all formerly tracked one another so closely that today, for instance, language differences can still be used successfully—and scientifically—not only to circumscribe and label separate “populations” in the Pacific (e.g., as different “ethnolinguistic groups,” ‘races,” and the like), but can also tell us how to reconstruct the prehistory and ancient migrations of separate and distinct “peoples” out into Oceania (Terrell et al. 1997).

It is generally considered impolite to say so, but the conventional word for this type of thinking is the word racism.

What seems astonishing is that racial thinking like this still frames how archaeologists, linguists, historians, social anthropologists, and human geneticists think about Pacific Islanders and write about their past. The most recent instance of this almost universal practice is possibly also the most revealing example of why otherwise informed scholars find themselves still under the spell of such an antiquated and unscientific idea.

Melanesians and Polynesians

As early as 1813 James Cowles Prichard was formally proposing—as others had earlier done more anecdotally—that the inhabitants of the Pacific Islands starting with New Guinea and neighboring places and moving on out eastward could be divided into “two principal classes.” In his own words (quoted in: Terrell et al. 2001):

The tribes which belong to the first of these are, strictly speaking, savages. They are universally in that rude unimproved state, which precedes all division of professions and employments. Consequently their political condition is that of perfect equality without any difference of ranks. Their physical character is of the rudest kind. Their form and complexion
approximate to those of the Negro.

Pritchard called these rude savages “the race of the Papuas.” Others would come to favor instead the term “Melanesians” (i.e., “black islanders”). He did not offer a name to use for the other—and supposedly superior—class of people except to say that such tribes were to be found in “the more distant regions of the Pacific Ocean.”

By 1843, his uncertainty about how to label the latter class of tribes had been resolved in favor of calling them “Malayo-Polynesians” since by then “a real kindred, or community of origin” had been established “by affinity of language” between islanders in Southeast Asia (i.e., “Malays”) and those in the more remote parts of Oceania, who were by then often labeled as Polynesians (i.e., “people of the many islands”).

Today the favorite label for the “affinity of language” noted by Pritchard and others in the 19th century between people in Polynesia and some of the inhabitants of Island Southeast Asia is the linguist’s label Austronesian. Nowadays, too, those said to be in Pritchard’s so-called class of savages are generally called “Papuans,” although the label “Melanesians” is also still used by some.

Racial redux

Under the headline “‘Game-changing’ study suggests first Polynesians voyaged all the way from East Asia,” Ann Gibbons, a writer at Sciencemagazine who had written previously about the origins of the Polynesians (Gibbons 1994, 2001), announced in surprisingly unqualified terms on 3 October 2016 that the identity of the first settlers of Polynesia was at last known, thanks to a paper then just published in Naturereporting on the first genome‑wide study of ancient DNA from prehistoric Polynesians (Skoglund et al. 2016). Lo and behold, their ancestors were ancient East Asian mariners “who swept out into the Pacific. It wasn’t until much later that Melanesians, probably men, ventured out into Oceania and mixed with the Polynesians.”

To clinch the story, she then quotes experts who apparently ought to know what they are talking about.

“The paper is a game‑changer,” says Cristian Capelli, a population geneticist at the University of Oxford in the United Kingdom, noting that that it settles a decades‑long dispute. By showing that the East Asians hopscotched past islands already populated by Melanesians without picking up their genes, it is also a case study in how culture can initially bar mixing between groups. “Farmers move in and don’t mix much with the hunter‑ gatherers,” says evolutionary geneticist Mark Thomas of University College London. “We see this again and again and again” elsewhere in the world.

Not so fast

The late population geneticist and mathematical ecologist Richard Levins is famous in scientific circles for once having declared in no uncertain terms that “truth is the intersection of independent lies.’’ Given that what Gibbons, Capelli, and Thomas are saying is intellectually—if not necessarily politically—racist, why are they so confident? Particularly since the claim being endorsed is based on DNA extracted from only four skulls dating to around 3,000 or so years ago (three from Vanuatu, and one from the Tongan Islands) compared with the DNA of less than 800 present-day individuals from 83 places in Asia and Oceania.

To a cautious statistical mind, such figures ought to raise the worry that not enough is known about human genetic variation in this part of the world to warrant going far out on a limb by declaring resolutely that science has now told us not only where the ancestors of the Polynesians came from, but also how.

Add to this concern the additional information that all four of the women in the archaeological sample from the Pacific display their strongest apparent genetic ties with Taiwan—currently the most popular place to start the purported ancient migration to Polynesia—and with the Philippines.* Does a modern comparative DNA sampling of 778 individuals from 83 places in Asia and Oceania tell us enough about genetic similarities and differences throughout this immense regionto overrule the reasonable doubt that linking the four prehistoric women with present-day people in Taiwan and the Philippines wasn’t exactly an unpredictable finding? Isn’t it reasonable to suspect this study might be biased, i.e., is an example of looking specifically for something—a genetic connection with Taiwan, in particular—where you most hope to find it?

Two alternative stories

The research report in Nature that Ann Gibbons wrote about in Science last October has 31 credited authors, a global mix of geneticists and archaeologists. Their report starts off with the assertion: “Pacific islanders today derive from a mixture of two highly divergent ancestral populations.” These authors then go on to tell us that there are two alternative stories—they call them hypotheses—about these two primal races (a word they do not use), and they say they now know which of the two to believe.

Both stories accept as true the unstated premise that biology, language, and culture co-vary closely with one another. The first story is an old tale still favored by some archaeologists (Bellwood 2011). If (a) race, language, and culture co-vary, and (b) Polynesians today speak languages of Southeast Asian origin (i.e., Austronesian, formerly called “Malayo-Polynesian”), then(c) it follows that the ancestors of the Polynesians came from Southeast Asia. The second story is a more recent alternative reconstruction of Polynesian origins (Green 2003). If (a) race, language, and culture co-vary, and (b) the so-called “Lapita cultural complex” archaeologically associated with the first settlers of Polynesia is a cultural mix of Southeast Asian and Melanesian traits, then (c)thePolynesians racially must also be of similarly mixed biological origin.

Needless to say, these collaborators would not have written their report if they had found they couldn’t adjudicate the right choice between these two alternative stories. And they do not disappoint us: “Our study has shown that many of the first humans in Remote Oceania had little, if any, Papuan ancestry, in stark contrast [an odd choice of words?] to the situation today.” And if so, the second story evidently can’t be correct, right?

But this is not all they have to conclude. In their estimation: “Systematic study of ancient DNA from throughout Remote Oceania should make it possible to provide a detailed chronicle of the population movements and sex-biased population mixtures that shaped the ancestry of present-day Oceanians.”

Should we accept as true what they tell us? Is there a better way to think about what they report? In other words, what’s the chance they have been barking up the wrong stories altogether?

*Only 14 of the 83 places in their comparative sample are located in Island Southeast Asia; 2 of these are on Taiwan and 6 in the Philippines. None of the other 69 localities is in the region between the Philippines and northern New Guinea except for a single sample of 10 individuals from Sulawesi. We return to these figures in Part 2 of this commentary.

References

Bellwood, Peter. 2011. Holocene population history in the Pacific region as a model for worldwide food producer dispersals. Current Anthropology 52: S363–S378.

Matisoo-Smith, Elizabeth A. 2016. Human biology and population histories in the Pacific–Is there such thing as a Lapita people?. In: The Routledge Handbook of Bioarchaeology in Southeast Asia and the Pacific Islands, edited by M. Oxenham and H. Buckley, pp. 389–408. Routledge, London.

Terrell, John Edward, John Edward, Terry L. Hunt, and Chris Gosden. 1997. The dimensions of social life in the Pacific: Human diversity and the myth of the primitive isolate. Current Anthropology 38: 155–195.